Do you have a real need to run PA 1.0 code? As far as I know,
linux only runs on PA 1.1 machines and later. Very few PA 1.0
machines are still running, and we have no way to test changes
other than to run it on current hardware. PA 1.0 support will
be removed at the time HP-UX 10 support is removed.

Regarding the regression, it would appear to have been introduced
when complex modes were added to GCC. I'm not quite sure when this
occurred, but it was before GCC 3.0 (the oldest version that I had
handy).